Chamber for culturing cells and method for making same

ABSTRACT

Disclosed is a method for making an incubator, as well as an incubator structure. The disclosed method includes molding a chamber body. The chamber body defines an interior and an opening to the interior, and a door is provided to selectively seal the opening to the interior. During the molding of the chamber body, a component is included in the chamber body. In a particular embodiment, the component may be a sensor, a bracket for receiving another part, a leg, an adaptor, a wire, a connector, a heating element, a window, a hinge, a label, indicia, or a gasket. Preferably, this method of creating a chamber involves rotational molding, although other methods of forming, such as stereolithography, are also possible as would be clear to one of ordinary skill in the art.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The subject application is a continuation-in-part of commonly owned, co-pending U.S. patent application Ser. No. 10/131,632, filed Apr. 24, 2002, the disclosure of which is herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject technology relates to incubators and a process for forming chambers, and more particularly, to a process for forming a cell culturing chamber such that the chamber includes components.

2. Background of the Related Art

Incubators are used to maintain environment sensitive specimens such as cells (e.g., human, animal, insect, mammalian and like embryos) under desirable conditions. The use of stainless steel and other metals in the fabrication of housings for incubators is well known in the art. Generally, the metal housing defines an interior chamber surrounded by a water jacket for maintaining temperature control. Direct heat may be applied to the interior and/or exterior of the chamber to maintain temperature control, with the chamber insulated to aid in maintaining the temperature at a stable level. Techniques have also been developed to maintain a constant flow of air and to filter the air within the interior chamber.

Several systems have been developed to provide access to and control of the conditions of the interior of an incubator. Some examples are illustrated in U.S. Pat. No. 6,013,119 to Cecchi et al., U.S. Pat. No. 5,792,427 to Hugh et al. and U.S. Pat. No. 6,225,110 to Cecchi et al., each of which is incorporated herein by reference in its entirety. For example, one parameter that is desirable to control within the incubator is the cleanliness of the air. Generally, an air circulation system includes a blower for forcing the air within the interior through a filtering mechanism and back into the interior. Sophisticated feedback mechanisms may be employed to maintain humidity and temperature within prescribed ranges.

While the fabrication of the metal housings for incubators is well known in the art, the associated fabrication process is relatively cumbersome. Such housings are formed through bending, forming, and then welding together various metal parts. This is a time consuming and difficult process, and results in a heavy structure. Further, the welded corners and joints require expensive polishing to provide a smooth surface that can be cleaned; poorly-performed polishing can lead to asperities that foster the deleterious growth of mold, spores, and other bacteria. In addition, the final interior chamber typically defines right angle corners that provide an area for undesirable contamination to collect and can be difficult to clean successfully.

Another disadvantage associated with fabricating incubators from metal is the difficulty in installing secondary components. For example, many incubators include sensors for monitoring temperature and humidity, ports for connecting sensors to external monitoring devices, adjustable feet for stable incubator placement, hinges for the attachment of doors, video cameras, air filtration units, and the like. When installing components such as these, brackets are attached by drilling holes through the incubator walls, finishing and cleaning the holes, attaching the brackets with fasteners, and the mounting the components on the brackets.

Issues similar to those outlined above are experienced when fabricating an incubator door. The door, like the rest of the incubator, must be insulated to limit heat exchange, and must seal with the chamber. A typical door often includes hinges and a sealing structure, and is composed of several distinct parts that must be assembled. Some incubators also include a second door, made of glass, which allows the contents of the chamber to be visible.

As appropriate for the specific application, a plurality of fixtures or support structures may exist within the interior of an incubator chamber. In the case of metal incubators, anchors are often spot-welded, at great expense and difficulty, to the interior of the chamber for securing shelving and other user selectable fixtures. In some cases, such shelving units may be configured to enhance air flow and access to specimens as taught in U.S. patent application Ser. No. 09/693,595 to Cecchi et al. and U.S. patent application Ser. No. 10/053,944 to Cecchi et al., each of which is incorporated herein by reference.

Recently, several disclosures have suggested forming incubators from plastic rather than stainless steel. For example, U.S. Pat. No. 5,958,736 to Goffe discloses an incubator composed of plastic. Use of plastic rather than stainless steel in forming an incubator has several advantages, including easier machining and lighter weight. However, while machining and movement of plastic incubators is facilitated, attaching multiple components to a plastic incubator remains expensive and time consuming. This issue is exacerbated by the fact that many incubator applications require a significant number of components related to monitoring and maintaining the interior environment. Unfortunately, Goffe does not address the issue of reducing the time or expense required to assemble the many components used in conjunction with an incubator.

There is a need, therefore, for an improved incubator, which permits easy and cost-effective attachment and assembly of multiple components, assures adequate cleanliness, and maintains desirable conditions for the specimens.

SUMMARY OF THE INVENTION

The present technology is directed to a new and improved chamber for storing cell cultures, as well as a new and improved method for creating a chamber. The disclosed structure and method provides for a chamber that permits easy and cost-effective attachment and assembly of multiple components, assures adequate cleanliness, and maintains desirable conditions for the specimens.

In a preferred embodiment of the method of the present invention, an incubator is created by molding a chamber body. The chamber body defines an interior and an opening to the interior, and a door is provided to selectively seal the opening to the interior. During the molding of the chamber body, at least one component is included in the chamber body. In a particular embodiment, the component may be a sensor, a bracket for receiving another part, a leg, an adaptor, a wire, a connector, a heating element, a window, a hinge, a label, indicia, or a gasket. Preferably, this method of creating a chamber involves rotational molding, although other methods of forming, such as stereolithography, are also possible as would be clear to one of ordinary skill in the art.

In another particular embodiment of the method of the present invention, an incubator is created by forming a chamber body, the chamber body defining an interior and an opening to the interior. During the forming of the chamber body, a door is formed substantially simultaneously with the chamber body such that the door and chamber exist as a unit. The door acts to selectively seal the opening defined by the chamber body. Preferably, the forming steps include rotational molding.

The present invention is also directed to a wall for an incubator. The wall includes a first layer and a second layer integral with the first layer. Preferably, successive rotational molding steps are employed to form the first and second layers, which are each composed of different materials. In a particular embodiment, the step of forming the first layer for the wall of the chamber includes forming a hollow, and the hollow is filled with a material. In another particular embodiment, the second layer completely surrounds the first layer. In still another particular embodiment, the wall includes a third layer integral with the second layer.

These and other unique features of the system disclosed herein will become more readily apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those having ordinary skill in the art to which the disclosed system appertains will more readily understand how to make and use the same, reference may be had to the drawings as follows.

FIG. 1 is a perspective view in partial cross section of an incubator constructed in accordance with the present invention, showing various components embedded in the chamber walls of the incubator, a chase area housing electronics, and a keypad for user inputs.

FIG. 2 is a cross-sectional view of a portion of the incubator of FIG. 1, the view taken along line 2-2 of FIG. 1 and showing several components embedded in the chamber wall of the incubator, the components having opposing ends that are laterally offset from one another and connected by wires that extend through the chamber wall.

FIG. 3 is a cross-sectional view of a portion of the incubator of FIG. 1, the view taken along line 3-3 and showing the double wall of the incubator chamber defining a hollow area.

FIG. 4 is an exploded perspective view of an incubator chamber and an associated door, the chamber including a raised feature that mates with a depression in the door to enhance sealing of the chamber opening when the door is closed.

FIG. 5 is a cross-sectional view of the incubator chamber of FIG. 4, the view taken along plane 5-5 and showing the double wall of the incubator chamber and the hollow area defined thereby.

FIG. 6 is a perspective view of an incubator chamber and door, the chamber and door together being of a lightweight monolithic construction and including a hinge formed as a unit with the chamber and door.

FIG. 7 is a perspective view of an incubator, in which the incubator chamber has a multi-part wall consisting of a core and a shell layer;

FIG. 8 schematically illustrates the two-step rotational molding process utilized to form the multi-part wall illustrated in FIG. 7.

FIG. 9 is a cross-sectional view of a portion of an incubator chamber, showing a double wall defining a jacket space, the outer wall of the double wall incorporating a threaded spout for allowing a matingly-threaded cap to seal the spout.

FIG. 10A is a side view of the bottom portion of an incubator chamber, showing hollows (in phantom line) defined by the chamber that receive feet.

FIG. 10B is a side view of the bottom portion of an alternative incubator chamber having chamfered feet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present technology provides a structure and formation process for incubators that overcomes many of the prior art problems associated with conventional incubators. The advantages, and other features of the process disclosed herein, will become more readily apparent to those having ordinary skill in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings, which set forth representative embodiments of the present invention and wherein like reference numerals identify similar structural elements.

Referring to FIG. 1, an anabolic chamber (or “incubator”), designated generally by reference numeral 100, includes a double-walled body portion 102 for defining an interior 104 which maintains specimens 106 in an environmentally controlled, clean environment. It is envisioned that the specimens are human embryo cultures and other like environmentally sensitive objects. The substantially box-shaped body portion 102 includes four outer walls 108, an upper ceiling 110 and a base floor (not shown). A jacket space 114 is defined between three inner walls 116 and the corresponding outer walls 108. An inner floor 118 allows the jacket space 114 to continue about the base floor of the body portion 102. Preferably, the jacket space 114 is filled with fluid (often water) to provide temperature stability. The jacket space 114 may also be filled with other substances, such as insulation. In another embodiment, an inner ceiling (not shown) allows the jacket space to continue about the upper ceiling of the body portion. In yet another embodiment, inner walls 116 are absent, and incubator 100 has no jacket space.

An opening 126 in the front outer wall provides access to the interior 104 within the body portion 102. A door 128 is secured to the front outer wall by a hinge 130 and selectively seals the opening 126. Adjacent to the opening, a keypad 132 integral with the outer wall 108 receives user input. The upper ceiling includes a perimeter ridge 134 and the base floor includes a recess (not shown). When multiple anabolic chambers 100 are stacked, the recess of the base floor receives the ridge 134 to secure the anabolic chambers 100 in place. Preferably, shelves 138 are included in the interior 104 of the chamber 100 for supporting specimens 106. A humidifying pan 140 is filled with distilled water to humidify the interior 104. The humidifying pan 140 receives a conduit 142 such that recirculated air passes through the humidifying pan via the conduit 142.

Referring still to FIG. 1, an intermediate wall 122 extends between the inner walls 116 and outer walls 108 on a side of the incubator 100 for defining a chase area 124. The chase area 124 of the anabolic chamber 100 stores additional instrumentation. Inputs from the keypad 132 are received by a control module 154 within the chase area 124 to facilitate controlling environmental parameters with the interior 104. Additionally, the control module receives inputs from sensors and the like within the interior 104 and displays the results on a readout panel portion of the keypad 132. The readout panel portion also provides indication of the current settings for the interior 104. Drive 28 receives a medium suitable for recording data related to the conditions within the interior 104. The drive 28 may receive CD ROMs, VHS tapes, diskettes, and the like and the data stored thereon may be video, acoustic, temperature, humidity, airflow, and the like data as is known to one of ordinary skill in the pertinent art. It is well within the skill of those of ordinary skill in the pertinent art to locate the chase area in another location as would be desired and apparent based upon review of the subject disclosure.

Referring to FIGS. 1 and 2, the anabolic chamber 100 is of a lightweight monolithic construction having a plurality of components 136 a-c included in body portion 102. Some components 136 a are included in body portion 102 such that they extend directly through solid material. Other components 136 b are included in body portion 102 such that they extend from inner wall 116 across jacket space 114 to outer wall 108. Still other components 136 c are included in body portion 102 such that they have a first end 137 a included in an outer wall 108, a second end 137 b included in an inner wall 116, and a conducting path 137 c connecting ends 137 a and 137 b, the conducting path 137 c allowing the two ends 137 a and 137 b to be laterally offset from one another while continuing to communicate. Such components 136 a-c may include, without limitation, a sensor, a bracket for receiving another part, a leg, an adaptor, a wire, a connector, a heating element, a window, a hinge, a label, indicia, and a gasket. In particular embodiments, components 136 a-c are actually several components connected together (e.g., a sensor, an adaptor, and a wire connecting the two). This incorporation of components 136 a-c directly into body portion 102 saves time in final assembly of the chamber 100 and creates a surface topography that facilitates cleaning the exposed surfaces of the interior 104 of the chamber 100. Further, the inclusion of adaptors in body portion 102 allows for parts to be interchanged or easily replaced. The ability to offset the two ends of a component allows, for example, for data to be collected at various locations within a chamber, but read at a common, conveniently-located user interface. In a particular embodiment, door 128 is similarly of a lightweight monolithic construction and includes components including, but not limited to, hinges, a window, and/or sensors.

Preferably, the body portion 102 of the anabolic chamber 100 is constructed using a rotational molding process. Rotational molding is a manufacturing option that allows for a monolithic design having integral features and components. Generally, the rotational molding process places a mold in a molding machine that has a loading, heating, and cooling area. Pre-measured plastic resin is loaded into each mold, and then the molds are moved into an oven where they are slowly rotated on both the vertical and horizontal axis. The melting resin sticks to the hot mold and coats every surface evenly. The mold continues to rotate during the cooling cycle so the parts retain an even wall thickness. Upon cooling, the parts are released from the mold. The rotational speed, heating and cooling times are all controlled throughout the process. As a result, what would be required from a plurality of pieces of stainless steel can be molded as one part, eliminating expensive fabrication costs. The process also has a number of inherent design strengths, such as consistent wall thickness and strong outside corners that are virtually stress free. However, other methods of forming an incubator in accordance with the present invention, such as stereolithography, are also possible, as would be readily apparent to one of ordinary skill in the art.

Rotational molding also allows selection of variable material, including materials that meet FDA requirements. It will be appreciated by those of ordinary skill in the pertinent are that polymer resin, plastic resin, composites, the like, and combinations thereof can be used as the material for the body portion. Further, additives can be selected to help make the resulting parts weather resistant, flame retardant, anti-microbial, mildew retardant and static free. Inserts, threads, handles, minor undercuts, fine surface detail such as snap-fit slots for engaging objects, and the like can be incorporated into the mold rather than as a later addition. Preferably, the corners of the interior are coved to allow for easy cleaning. Temporary modifications to an existing mold for a particular application allow further product customization. Thus, all of the necessary features are formed integral to the body portion and the resulting smoother surface of formed plastic is easier to clean.

Referring now to FIG. 3, one or more elements 152 maintain the temperature of the fluid within the jacket space 114 and therefore the interior 104. In an embodiment without the jacket space 114, an element 152 more directly maintains the temperature of the interior 104. In the preferred embodiment, the element 152 heats the interior 104 to promote anabolic growth. It is envisioned that the element 152 may heat and/or cool the surface in contact therewith as would be known to one of ordinary skill in the pertinent art. Also, it is to be appreciated that at times the remaining description refers to a heating element in the singular for simplicity although a plurality may be used. Preferably, the elements 152 are flexible to adhere to the contour of the anabolic chamber 100 and deliver heat precisely and locally over the area to be heated. Preferably, the elements 152 are a fiberglass reinforced silicone rubber element available from Electro-Flex Heat of Bloomfield, Conn. The desirable properties include resistance to temperature extremes, moisture, weathering, radiation, fungus, inertness from chemical attack, high dielectric strength and flexibility. Further advantages are that odd shapes, holes, cutouts, profiled watt densities, and multiple voltages can be accommodated. In a preferred embodiment, the elements 152 are directly bonded to the area to be heated with pressure sensitive adhesive. Alternatively, fasteners such as eyelets, lacing hooks, hook-and-pile straps, spring clips, snaps and the like can be included in the rotational molding process for retaining the elements 152. When an anabolic chamber 100 is reconfigured internally and externally, the element 152 can be temporarily removed or moved to a new location on the anabolic chamber 100. It is also envisioned that thermostats of various types and temperature sensors such as thermistors, thermal-fuse, or thermocouples can be built into the heater and provide feedback to the control module 154 (see FIG. 1). In another preferred embodiment, the element 152 is molded directly over the anabolic chamber 100 to insure an efficient contact area for heat transfer.

Still referring to FIG. 3, support ribs 156 extend between adjacent inner walls 116 and outer walls 108 and serve as latent features for allowing modification of the chamber 100 to provide access to the interior 104 of the chamber 100. Preferably, chamber 100 also includes indicia for locating the ribs 156. Upon locating a desired latent feature, a conventional drill and bit is used to reconfigure the anabolic chamber 100. For example, one can use a drill to form a bore 157 through the rib 156 to form, e.g., a port. The bore 157 can serve as a pass-through such as disclosed in U.S. Pat. No. 6,225,110 to Cecchi et al. and incorporated herein by reference in its entirety. The bore 157 can be tapped for engaging a threaded fastener or used temporarily and resealed with plugs. Provided the bore 157 is formed within the structural rib 156, in cases where jacket space 114 contains fluid, the structural rib 156 still supports the sidewalls without leaking. Alternatively, the support rib 156 may be partially drilled out and used similarly as a mounting block as described with reference to FIG. 3. Consequently, any apparatus or component that can be mounted such as by screws can be secured to the anabolic chamber 100 at various locations. For example, electrical power boxes, additional shelf brackets, sensor brackets, filter units, cameras, data recorders and the like may be mounted inside or outside the anabolic chamber 100 as would be appreciated by those of ordinary skill in the art based upon review of the subject disclosure. The chamber 100 may also contain a pin and/or a void, which may or may not be threaded or present at initial fabrication, at various locations.

Referring to FIG. 4, in another preferred embodiment, an opening 226 in the body portion 202 provides access to the interior 204 of chamber 200. Incorporated into body portion 202 are inserts 229. A door 228 includes one or more hinges 230, which are received by inserts 229 to secure the door 228 to the body portion 202 and allow the door 228 to selectively seal the opening 226. In another preferred embodiment, the hinge or holding brackets are included with the body portion of the chamber, and the door incorporates inserts such as brackets for receiving the hinges or hinges. In one embodiment, the brackets are simple flanged posts to mate to hinges.

Referring still to FIG. 4, door 228 has a depression 232 that faces towards chamber 200 when door 228 is attached to chamber 200 with hinges 230. Chamber 200 includes a raised feature 233 that protrudes from wall 208 and circumscribes opening 226. Raised feature 233 mates with depression 232 when door 228 is closed. This mating of raised feature 233 and depression 232 effectuates a seal between door 228 and chamber 200, and removes the need for a separate gasket. Preferably, the raised feature 233 is composed of a compliant material, such that raised feature 233 conforms to the depression 232 to enhance the seal. For example, chamber 200 may be formed by a first rotomolding step, and raised feature 233 is then formed by a second rotomolding step utilizing a more compliant material. Door 228 also includes an indentation 231 that acts as a handle, allowing a user to grip the indentation 231 when opening and closing the door 228. In another particular embodiment, the wall 208 and or raised feature 233 includes a groove that circumscribes the opening 226 and receives a conventional gasket. It is also envisioned that such a groove could be on a portion of the raised surface 233 that is perpendicular or parallel to the wall 208. In still other particular embodiments, door 228 includes either a raised feature acting as a gasket or a groove containing a conventional gasket. In still another particular embodiment, door 228 includes an annular channel that corresponds to the gasket-like raised feature 233 of chamber 200, such that the surface area involoved in the sealing of the door 229 and chamber 200 is increased.

Referring to FIG. 5, wall 208 of anabolic chamber 200 is a multi-part wall. Wall 208 includes an interior layer 262 and an exterior layer 260, the interior layer 262 defining a hollow area 264. The interior layer 262 and exterior layer 260 may be composed of different materials that serve different functions. For example, interior layer 262 can be composed of insulating material while exterior layer 260 is composed of conductive material, thereby facilitating heat transfer in the plane of the wall 208 but not in transverse directions. Other material types, targeted at serving different functions, are also possible. In a particular embodiment, hollow area 264 is filled with a substance, such as water or insulating material. In another particular embodiment, interior layer 262 is formed of a material that expands over time, thereby increasing the porosity of the material and giving it insulating properties. An example of such a material is polyurethane. In another particular embodiment, wall 208 is comprised of more than two layers, the layers being composed of similar or different materials. Such a multi-part wall can be formed, for example, by employing successive rotational molding steps, and can be used to create the double wall structure of FIG. 1 (i.e., inner walls 116 and outer walls 108 are each multi-part walls). In a particular embodiment, door 228 is similarly a multi-part structure. In situations where it is desirable to form the layers of the wall of different materials, this can be accomplished by performing a first rotational molding step with a first material, stopping the process and adding a second material, and then performing a second rotational molding step.

Referring to FIG. 6, in another particular embodiment of an incubator 300, body portion 302 and door 328 together are of a lightweight monolithic construction. For example, incubator 300 may be formed by rotational molding, such that body portion 302 and door 328 are formed simultaneously and as a unit. A hinge structure 330 connects door 328 to body portion 302 and allows door 328 to selectively seal opening 326. In a particular embodiment, hinge structure 330 is formed by rotational molding around a conventional hinge or other articulating structure that is included in the mold, although other methods for forming hinge structure 330 are available and well known to those skilled in the art. For example, hinge 330 may include a solid, resiliently flexible structure, such as a reinforced silicone sheet, which is molded around in forming body portion 302 and door 328. Alternatively, hinge 330 may be formed by including a thinner section of rotationally molded material between and connecting body portion 302 and door 328.

Referring to FIG. 7, in another preferred embodiment, wall 408 includes a core 462 surrounded by a shell 460. Core 462 and shell 460 may be composed of different materials or of the same material. In a particular embodiment, core 462 may be formed of a material that later decomposes, such that the final core 462 of wall 408 consists of gas. An opening may be included in the shell layer 460 during formation, such that the gases formed by the decomposing core 462 may escape. Alternatively, core 462 may be composed of a material that decomposes into a gas that diffuses through shell layer 460.

Referring to FIGS. 7 and 8, in a particular embodiment, the process for creating the core 462 and shell 460 of wall 408 is divided into two steps. First, molding is performed to form the core 462 in the desired final shape. Next, molding is stopped and, if desired, molding material is changed. Molding is then resumed to form the shell layer 460. This process is similar to that described in accordance with the multi-part wall 308 illustrated in FIG. 4.

Referring to FIG. 9, as mentioned earlier, in a preferred embodiment, jacket space 514 is filled with water, insulating material, or some other substance. The filling of jacket space 514 with material, or the exchange of one material for another, is facilitated by incorporating into outer wall 508 a spout 570. Spout 570 is threaded to allow a matingly-threaded cap 572 to seal the spout 570 and prevent the contents of the jacket space 514 from escaping. In another preferred embodiment, the spout extends into the jacket space and is female threaded, and the cap has a male threaded portion that extends into the spout to seal the jacket space.

Referring to FIG. 10A, in a preferred embodiment, chamber 600 defines hollows 680 for receiving feet 682. Alternatively, the feet 682 can be frictionally fit into the hollows 680, or, the feet 682 can be loosely contained in hollows 680. In another preferred embodiment, the hollows and the feet can be matingly-threaded, thereby allowing the chamber to be leveled by independently screwing each of the feet into the hollows to appropriate amounts. In still another preferred embodiment shown in FIG. 10B, feet 683 can be incorporated into the chamber 600, for example, by performing rotational molding of the feet 683 while forming the chamber 600.

While the technology has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and/or modifications can be made to the invention without departing from the spirit or scope of the invention as defined by the appended claims. 

1. A method for creating an incubator comprising the steps of: a) molding a chamber body, the chamber body defining an interior and an opening to the interior; b) during the molding of the chamber body, including at least one component in the chamber body; and c) providing a door to selectively seal the opening.
 2. A method as recited in claim 1, wherein the component is selected from the group consisting of a sensor, a bracket for receiving another part, a leg, an adaptor, a wire, a connector, a heating element, a window, a hinge, a label, indicia, and a gasket.
 3. A method as recited in claim 1, wherein the step of molding is by rotational molding.
 4. A method as recited in claim 1, wherein the step of providing the door includes: molding the door; and during the molding of the door, including at least one component in the door.
 5. A method as recited in claim 1, wherein the chamber body includes a raised, annular feature that contacts a surface of the door to effectuate sealing of the opening.
 6. A method as recited in claim 1, wherein the chamber is fabricated from one or more of the materials selected from the group consisting of polyurethane, polycarbonate, polyethylene, polytetrafluoroethylene, an additive, polycarbonite and combinations thereof.
 7. A method as recited in claim 1, wherein the step of molding the chamber body includes the steps of molding the chamber body of a first material and molding about the first material with a second material.
 8. A method as recited in claim 7, wherein one of the materials expands after application to form an insulating layer.
 9. A method for creating an incubator comprising the steps of: forming a chamber body, the chamber body defining an interior and an opening to the interior; and during the forming of the chamber body, forming a door substantially simultaneously with the chamber body so that the door exists as a unit with the chamber body and selectively seals the opening.
 10. A method as recited in claim 9, wherein the steps of forming are by rotational molding.
 11. A method as recited in claim 9, further comprising the step of including at least one component in the chamber body and door unit during the forming of the chamber body and door unit.
 12. A method as recited in claim 9, further comprising the step of forming a hinge structure during the forming of the chamber and door unit, such that the hinge exists as a unit with the chamber and door and allows the door to move with respect to the chamber.
 13. A method as recited in claim 9, wherein the door is formed to include a raised, annular feature that contacts a surface of the chamber body to seal the opening.
 14. A wall for an incubator comprising: a first layer; and a second layer integral with the first layer.
 15. An incubator wall as recited in claim 14, wherein the second layer completely surrounds the first layer.
 16. An incubator wall as recited in claim 14, further comprising a third layer of the wall integral with the second layer.
 17. An incubator wall as recited in claim 14, wherein the first layer of the wall is composed of a different material than the second layer of the wall.
 18. An incubator wall as recited in claim 14, wherein the first layer is composed of a material that expands after application to form an insulating layer.
 19. An incubator wall as recited in claim 14, wherein the first and second layers are formed by successive rotational molding steps.
 20. An incubator wall as recited in claim 14, wherein the wall is a double wall that defines a hollow space, the hollow space containing a material for affecting a performance of the wall. 